不同速度输注异丙酚对低温体外循环期间患者麻醉深度的影响

The influence of different infusion speed of propofol on anesthesia depth in patients undergoing hypothermic cardiopulmonary bypass

目的探讨不同速度输注异丙酚静脉麻醉下低温体外循环期间大脑状态指数（cerebral state index，CSI）及爆发抑制比（burst suppression ratio，BS％）的变化。方法择期行低温体外循环下心脏瓣膜置换手术患者44例，年龄（18～60）岁。随机分为两组，每组22例。麻醉诱导采用静脉注射异丙酚1mg／kg-1．5mg／kg，芬太尼10μg/kg，维库溴铵0．1mg／kg。麻醉维持采用持续静脉输注异丙酚4mg·kg^-1·h^-1（P4组）或6mg·kg^-1·h^-1（P6组），芬太尼5μg·kg^-1·h^-1。记录体外循环（cardio pulmonany bypass，CPB）前5min（T0）、CPB后2min（T1）、CPB开始后30min（T2）、CPB开始后60min（T3）、停CPB后15min（T4）时的CSI、BS％、鼻咽温度、平均动脉压（MAP）、心率（HR）。结果CPB期间两组的CSI均下降，与体外循环前比较差异有统计学意义（P〈0．05或0．01），P6组CPB 30min、60min的CSI与P4组比较为差异有统计学意义（P〈0．01）。P6组在CPB 30min、60min时出现爆发抑制比，与CPB前比较为差异有统计学意义（P〈0．01），与P4组比较为差异有统计学意义（P〈0．01）。结论低温CPB期间持续输注异丙酚6mg·kg^-1·h^-1时，CSI处于较低水平，BS％明显增多，应适当减少异丙酚的输注速度，以维持合适的麻醉深度。

Objective To investigate the changes of the cerebral state index （CSI） and burst suppression ratio （ BS% ） with different infusion speed of propofol during hypothermic cardiopulmonary bypass. Methods Forty-four patients aged 18-60 years undergoing elective cardiac valve replacement under hypothermic CPB were enrolled in this study. The CSI and BS% were used to measure sedation depth. Anesthesia was induced with fentanyl 10 μg/kg and propofol 1.0 mg/kg-1.5 mg/kg. Tracheal intubation was facilitated with vecuronium 0. 1 mg/kg and controlled ventilation was performed. Anesthesia was maintained with intravenous propofol infusion at a speed of 4 mg·kg^ - 1· h^ - 1 （ group P4 ） or 6 mg · kg^ - 1 ·h^ - 1 （ group P6 ） , and with fentanyl infusion （ 5 μg· kg^ - 1 ·h ^- 1 ） and vecuronium bolus. CSI, BS% , nasopharyngeal temperature, MAP and HR were measured and recorded at 5 min before CPB, 2 min, 30 min, 60 min of CPB, and 15 min after the end of CPB. Results The CSI and temperature generally declined during CPB （P 〈 0.05 or 0. 01 ）, and returned to pre-CPB values after separation from CPB in the two groups. The CSI and BS% were significantly lower in group P6 than that in group P4 at 30 and 60 rain of CPB （P 〈 0.01 ）. Conclusion The CSI was lower and the BS% was higher with propofol anesthesia at an infusion speed of 6 mg·kg ^- 1· h^- 1 during CPB, indicating that an appropriate reduction of propofol infusion speed was necessary to maintain a suitable anesthesia depth.